Air supply device for fireboxes or the like



v13%- 1941- J. G. ENGELHART 2,265,131

AIR SUPPLY- DEVICE FOR FIREBOXES OR THE LIKE Filed Sept. 6, 1940 TQLWHIHP 26 I. 926/- 3mm Patented Dec. 9, 1941 AIR SUPPLY DEVICE FOR FIREBOXE-S OR THE LIKE John G. Engelhart, Atlanta, Ga.

Application September 6, 1940, Serial No. 355,673

2 Claims.

My invention relates to a device for providing additional air supply to a burning fuel bed of a furnace, boiler, stove, or the like.

An important object of the invention is to provide a device of the above-mentioned character for supplying air over or adjacent to the upper surface of a burning fuel bed.

A further object of the invention is to provide a device of the above-mentioned character which will pre-heat the air in an efficient manner before supplying the same in proximity to the burning fuel bed.

A further object of the invention is to provide means for distributing the incoming air throughout the device so that it is discharged in a substantially uniform manner throughout the entire length of the device.

A further object of the invention is to provide exterior. and interior heat transfer fins which are in heat contacting relation, whereby the maximum heat exchange is effected between the burning fuel and the air passing through the device.

A further object of the invention is to provide a device of the above-mentioned character Which is adapted to be placed upon the grate of the fire box and is formed in a separate unit from the furnace or boiler.

A further object of the invention is to provide a device of the above-mentioned character which is of simple construction and which may be manufactured cheaply.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawing forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

Figure l is a transverse section through the air supplying device, taken on line ll of Figure 2, looking in the direction of the arrows,

Figure 2 is a vertical section taken on line 2-2 of Figure 1, looking in the direction of the arrows,

Figure 3 is a similar view taken on line 33 of Figure 1, looking in the direction of the arrows,

Figure 4 is a similar view taken on line 4-4 of Figure 1, looking in the direction of the arrows, and,

Figure 5 is a fragmentary perspective View of the device.

In the drawing, wherein for the purpose of illustration is shown a preferred embodiment of my invention, the numeral H) designates the front wall of, a fire box Ill of a stove, furnace, boiler or the like, having a fuel door II at its front end which is opened for the admission of fuel. The fire box is provided with the usual grate l2 forming an ash pit I3. The entrance of air into the ash pit is controlled by the usual dampers and this air passes upwardly through the grate to support the combustion of the fuel in the fuel bed l4. Y

My air supplying device comprises a shell 15, formed of iron or any suitable material. This shell is substantially L-shaped in vertical crosssection and includes a horizontal compartment l6 and a vertical compartment I l, in free communication with each other, as shown. The shell 15 is adapted to be arranged directly upon the grate l2 within the fire box, preferably next to the front wall [0, and the shell l5 preferably extends throughout the entire width of the fire box, Figure 2. The shell I5 is provided with exterior heat exchange fins l8, which are preferably equidistantly spaced in a direction longitudinally of the shell [5. The fins I8 have vertical portions I 9 extending over the end of the horizontal compartment l6, horizontal portions 20 extending over the top of the compartment l6, vertical portions 2| extending over the side of the vertical compartment I1, and generally horizontal portions 22 extending over the top of the vertical compartment H. The top of the vertical compartment I1 is preferably curved or inclined, as shown at 23, extending upwardly in a rearward direction from the front wall ID, to deflect the heated air rearwardly, as shown. The fins I8 are preferably integral with the shell 15 and therefore have contacting relation therewith. Arranged within the shell l5 are interior heat transfer fins 24, which extend through the horizontal compartment Hi and across the vertical compartment ll. The fins 24 correspond in number and arrangement to the fins l8 and are in alignment with the fins l8 and are preferably integral with the shell I 5 and hence integral with and in contacting relation with the fins l8. This aids in the efficiency of the heat transfer. The horizontal fins 24 have their lower edges 25 spaced from the bottom wall 26, as shown, and this bottom wall is provided with an elongated air inlet opening 21, preferably arranged adjacent to the rear ends of the fins 24 and extending across the same and extending throughout substantially the entire length of the compartment 16. The top edges 28 of these fins 24 extend across the lower end of the vertical compartment H and are, of course, spaced from the top of this compartment. The fins 24 are formed integral with the shell I 5 at their forward ends, at their upper edges, and at their rear ends. While the fins I8 and 24 are preferably formed integral with the shell l5, they may be secured to the shell in any other suitable manner for effecting contact with the shell. The fins 24 are equidistantly spaced throughout the length of the shell I5, and in addition to effecting heat exchange, also cause the air to be uniformly supplied within the Vertical compartment 11. The vertical compartment I1 is provided in its rear vertical face with elongated vertical slots 29, for the discharge of the heated air into the fire box 10'.

The operation of the device is as follows:

The air enters the ash pit l3 and is pre-heated therein and a portion of this air passes through the grate to the bottom of the fuel bed Hi, to support combustion, in whole or in part. A portion of this pre-heated air passes through the grate i2 and enters the horizontal compartment I6 through the opening 2'! and thentravels longitudinally within the horizontal compartment throughout the entire length of this compartment and in contact with the horizontal fins 24. The exterior fins 18 are heated by radiation and by contact with the heated gases in the fire box 'or the burning fuel and these exterior'fins transfer this heat by contact to the interior fins 24, which inturn heat the incoming air, by contact and radiation. The air is also heated by radiation and'co'nt'act of the walls of the compartment It. The further heated air then passes into the vertical compartmentand is heated by radiation from andcontact with the walls of this vertical com- I partment and then discharges in a rearward direction over the horizontal compartment l6 and in proximity to the burning fuel bed l4, and preferably over the same. The outlet openings 29 being arranged near and between the vertical portions of the fins Hi, the discharging air contacts therewith for further heating of th air. It is thus seen that the air is heated in an eflicient manner and is then supplied to a point adjacent to the burning fuel bed, preferably at its top, to aid in effecting complete combustion of the fuel. It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

' Having thus described my invention, what I claim is;

1. An air supply device to be arranged within a fire box having a grate, said device comprising a shell to be arranged upon the grate, said shell comprising an elongated substantially horizontal compartment and a substantially vertical compartment in communication with one end of the horizontal compartment and projecting above the same, the horizontal compartment having a bottom wall, said bottom wall being provided with an air inlet opening extending throughout substantially the width of the horizontal compartment, said opening being disposed adjacent to th end of the horizontal compartment which is remote from the vertical compartment, the air inlet opening causing the incoming air to travel throughout substantially the entire length of the horizontal compartment before entering the vertical compartment, the vertical compartment having a rear vertical face provided with spaced elongated slots, transversely spaced exterior fins having rear vertical portions extending over the rear vertical end of the horizontal compartment and horizontal portions extending over the top of the horizontal compartment and vertical portions extending over the rear vertical wall of the vertical compartment, the fins being arranged between the vertical slots and contacting with the parts of the shell, and horizontal interior fins extending longitudinally of the horizontal compartment and contacting with the top Wall and the rear vertical wall of the horizontal compartment and extending across the vertical compartment, the interior fins being transversely spaced and arranged substantially in alignment with the exterior fins, the interior fins being spaced from the bottom wall of. the horizontal .compartment, Q

2. An air supply device to be arranged within a fire box having a grate, said device comprising a shell including an elongated substantially horizontal compartment and a substantially vertical compartment'in communication with one end-of the horizontal compartment and projecting above the same, the horizontal compartment having a bottom wall which is provided with an air inlet opening, said opening being disposed remote from the vertical compartment, the vertical compartment having a rear vertical face provided with spaced outlet openings, transversely spaced exterior fins carried by the top of the horizontal compartment and extending longitudinally of the same and also extending over the rear vertical wall of the vertical compartment, the fins being arranged between the outlet openings, and'horizontal interior fins secured to the top of the horizontal compartment and extending longitudinally thereof, the interior fins extending across the lower end of the vertical compartment, the interior fins being transversely spacedj JOHN G. ENGELI- IART. 

